Matt, I am not sure that you accurately captured the heart of the thesis with your headline. Although, to be fair, it is a fair debate question.
Still, I have to point out, increased risk to an existing weapon platform is a given to any long standing system. The bad guys will always look for ways to defeat it and the good guys will always look to counter those ways.
What is probably the best way to discuss this: is there absolutely no (or very little) projected utility (including new uses) in future operations? All foreseeable and even unconventional speculation of future military operations see a need for airborne assets and ground force employment/delivery. Global logistics for transportation and support of forces always includes water commons. That being said, the debate should move to the next step: is the current design of US aircraft carriers one that offers the most utility for future operations?
We do know that carriers do more than force projection, they also offer a very visible vehicle to show national resolve or attention in an area. Psychologically, it projects an image of incredible power (of course, if one were ever sunk due to enemy action, the reverse psychological effect would be devastating to US forces). Those are important considerations and can not be forgotten or ignored, those are invaluable force multipliers and bad guy deterrents.
However, there are some meritorious critiques. Current carriers are limited in numbers, a single destruction will render a significant degradation in capabilities of the US naval force projection percentage. There is very little platform redundancy. They do make huge targets, easily detected and tracked by near peers. They tie up significant carrier battle group resources in single asset protection. Naval air range has been degraded due to the need to stay out of increasing defensive weapons of the bad guys.
An out of the box question to ask, can we still get the same capacity with improved technology and smaller hulls? Can we shrink the size of line carriers, perhaps then increasing the number of hulls (platform redundancy) which could offer more mission profiles simultaneously in both same geographic areas and dissimilar geo locs. Could a rethought size hull offer better penetration (and therefore increasing strike depth for naval aviation) and lower detection probability by bad guys? More hulls also forces the bad guys to devote more resources to track those hulls.
Smaller hulls do not necessarily mean less aviation assets. With the pending advent of UCAVs (and the Navy seems further along in that development than the AF), you could have both more capability and significantly more assets (which means longer sustained high ops tempo), more aggressive mission prosecution (missions that might have been declined due to high risk to human life, might be more inclined to be accepted with UCAVs).
Multiple hulls could also open up opportunities to prosecute high importance missions that have to be declined because we only have a few carriers underweigh at any one time. Consider, if a carrier is on strike ops, it will not be pulled to provide C2 and support for a tidal wave contingency aid. If a hurricane hits domestically, an at port smaller carrier could prep and respond faster than a full up carrier and be providing relief. Perhaps operationally, they could sail surveillance missions in the southern hemisphere for drug interdiction and narcoterror finance intercept.
There might be a manpower cost, but whereas before budget caps and soaring retirement costs prohibited manpower increases, but with military retirement reform, that may no longer be the case.